The Outdoor Research Alpine Bivy Sack is a mini-shelter with extra features to make it more versatile and comfortable. It’s top of the line in quality and effectiveness. We’re going to break down the various elements of a good bivy sack in this Outdoor Research Alpine Bivy review, to help you decide if it’s the one you need.

What is a Bivouac Sack?

The bivouac sack, or bivy sack, began as a temporary emergency shelter. It’s like a waterproof cover for a sleeping bag, but it also adds insulation and protects the user from the elements. In its most basic form, a bivy sack simply covers and protects.

Bivy sacks are not exactly like tents, although they do enclose you and your sleeping bag completely. Over time, however, the bivy has evolved into the shelter of choice for ultra-light campers and hikers.

Back to the main topic, let’s have a deeper look at the Outdoor Research Alpine Bivy Sack.

Our Rating:

Pros
  • One benefit of a bivy is that it sets up much more quickly than a tent. There are usually loops for stakes, and they keep the structure in place.
  • Bivy sacks provide more warmth than a tent because your body heat is retained inside. There’s also the benefit of layers that keep the warm air in: sleeping pad, sleeping bag, and bivy.
  • A Bivy can be adapted for warm or cold weather by adjusting the weight of the sleeping bag inside.
Cons
  • One drawback of a bivy over a tent is that there’s no room for gear, so it gets exposed to the elements.
  • Condensation can be a problem in such a small space as well. Proper ventilation is important to keep moisture from building up inside.
  • Sometimes a bivy can seem confining, which is why various makers have developed techniques to give some clearance room inside.
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Key Features

Bivy sacks are the protection of choice for those who will be outside in the weather but need to travel light. This includes mountaineers, hikers and soldiers. Besides being lightweight, they’re easy to set up and they help you retain body heat in the cold. Here are some of the main features that a good bivy should have, and how the Outdoor Research Alpine Bivy stacks up.

Waterproofing

One of the two main features that users seek is waterproofing. The Alpine Bivy is made with Gore-Tex Respiration Positive membrane, a step up from the original Gore-Tex fabric. It allows water vapor to vent through the fabric without letting rain or snow inside.

Insulation

Protection from the cold is the second most important feature that users look for. Most bivvy sacks add a few degrees of insulation from the outdoors. Combined with your body heat, this makes it warm enough to sleep even when it’s cold outside.

Ease of Setup

One of the benefits of a bivy over a tent is quick setup. The Alpine rolls out easily and there are straps inside to secure the sleeping pad. A cell phone, watch and other small items can be stashed in the mesh bag attached to the inside. Loops and stakes are usually included to hold the bivy in place. The Alpine has five stake loops and a guy line loop.

Comfort

Having the right sleeping bag pad is one way to ensure the most comfort. It’s also important to have a bivy that’s large enough for your needs. The Alpine bivy includes a flexible pole that threads into the top of the shelter to keep the material off your face.

Ventilation

Because of the small enclosed space, bivy sacks can be prone to having condensation inside. Some ways of dealing with this are adding vents and covered zippers that can be partially opened. The Alpine’s flexible frame helps provide more breathing space, which also helps prevent condensation.

Weight/Compactness

The weight and compactness of a bivy determine whether it can be used for hiking and mountaineering or just as a shelter for light camping. The ones that we’re reviewing include lightweight stakes. This adds a bit to the load, but it’s well worth it for keeping a bivy in one place.

Cost

One thing to take into account with the cost is whether the bivy is part of a set that includes a sleeping bag, or if it only includes the outer cover.

How to Set up a Bivy Sack

Outdoor Research provided a video on how to set up their bivy sacks. This is especially useful if you are new to this type of shelter.

Detailed Review

Waterproofing - 5/5
To be truly waterproof in most conditions, the seams of the bivy need to be factory sealed like the ones on the Alpine Bivy. The Hydroseal Floor and taped seams keep the bivy dry.
Insulation - 5/5
The Alpine seems to provide about 10 degrees of extra warmth, which is about the highest a bivy can be expected to achieve by itself.
Ease of Setup - 4.5/5
The loops provided allow you to stake the Alpine bivy. This provides some tension and keeps it in shape and in one place. Although it takes a few minutes to stake the bivy, it’s also much easier to slide the pad and sleeping bag inside once it’s staked. Maintaining the shape also helps the flexible pole do its job of keeping head space available.
Comfort - 4.5/5
Any bivy is going to be a tight space, which some outdoor enthusiasts find oppressive. The head space provided in the Alpine Bivy helps alleviate the sensation of being confined. It’s large enough to fit a 6.5-foot male or to keep shoes and a pillow inside.
Ventilation - 5/5
The mesh screen over the head area provides excellent ventilation and the mesh is fine enough to keep out even the small ‘no-see-um’ type insects. Overlapping fabric and zippers allow ventilation even if it’s raining outside the shelter.
Weight & Packed Size - 5/5
This lightweight bivy will ensure that it won’t be the first thing in the backpack you complain when you hike for a long time. When packed, it won’t take up much of the space in your backpack.
Cost - 3/5
Unfortunately good stuff comes with a price, this bivy is considered above average on the price point.

Overall Score:

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How Does It Compare To Others?

Military Modular Sleep System

The Military Modular Sleep System is completely waterproof, even in rain and snow. It is military-issue equipment and does the job well. There’s no built-in ventilation, however, so a tarp or other covering would allow you to zip open the bivy slightly to create a vent.

This model provides superior insulation compared to the others. Part of the reason is that, as the name states, it’s a modular system. The MM comes with two custom fitted sleeping bags, a lighter and heavier one, and they can be used together. Users have reported camping in near-freezing weather with only the MM as protection and staying warm all night.

The bivy itself requires no setup. The system of three compression/sleeping bags is fairly straightforward, with the pieces snapping together to keep them from getting tangled up.

The Military Modular is comfortable to sleep in, but it doesn’t have the pole support to keep the material off your face. It also has a limit to the size of the user, up to about a 6-foot-tall male.

This bivy isn’t as well-ventilated as some of the others. It zips completely closed, ‘mummy-style’, without vents. This also leads to problems with condensation.

Weight is not as light as the Alpine Bivy so if this might not be a great choice if you are doing ultra-light backpacking.

Snugpak 92860 Stratosphere

The Snugpak is similar to the Alpine, with factory-sealed seams and a canopy above the head and shoulders. The zipper seals with overlapping Velcro strips to keep cold and moisture out.

With a sleeping bag and mat, the bivy compares to army issue equipment as far as excellent insulation from the cold, even in near-freezing temperatures.

The Snugpak rolls out easily and has loops to stake it to the ground. There are two canopy poles that snap into place easily. The zipper down the side makes it easier to get in and out of the bivy. The unit is also easy to take down and pack up and takes up very little space.

The Snugpak canopy has two poles, providing more flexibility for arranging the space above. It will fit up to a 6-foot male comfortably, and it includes a mesh screen to keep out bugs. It’s roomy enough inside to keep a small pack and a weapon, as well as shoes. There’s also a mesh bag for a lantern or small items. In an emergency situation, two people could possibly fit inside.

The Snugpak has a mesh ventilation area at the back of the bivy that helps prevent condensation inside the bag. There’s also a vent in the head area with a fly cover that stakes down to prevent rain from getting in.

The weight of this bivy is higher than the rest so you might want to look elsewhere if you consider weight as an important factor.

Aqua Quest Hooped Bivy Tent

With heat-taped seams and a waterproof coating, the Aqua Quest has a high rating for being waterproof, yet has good breathability.

The insulation is excellent, and users have slept in a sleeping bag inside the bivy in complete comfort during near-freezing temperatures.

The Aqua Quest is fairly easy to set up, but it does take time to stake it out to give the extra room inside.

The head and shoulder area is raised with a hoop and gives more clearance than any of the others, with about 3 inches of headroom. The Aqua Quest will fit up to a 6.5-foot male comfortably and it has a bug mesh panel as well as a clear panel to look outside the shelter. The tie-down system has stiffeners in the foot area to keep the fabric away from your legs.

The mesh bug netting is more than just a panel. It covers the entire top third of the bivy, creating great ventilation during warm weather. An air vent is also included in the head section.

Looks like Alpine Bivy is the lightest as compared to the rest so definitely consider it if you are looking for a lightweight bivy.

Should you buy?

The ratings alone do not paint a picture of which product is the best for you. It depends on how much protection and space you need, for one thing. We gave the Outdoor Research Alpine Bivy an almost perfect score with our 5-point rating system. It has an average weight and compactness compared to other bivy-only setups. However, it’s pricier than similar products.

A less expensive model, the Snugpak, also got a perfect score. The slightly narrower frame is offset by the ease of getting in and out with the side zipper of the Snugpak. It also has a pole system to keep the fabric off your head and shoulders, and it’s more flexible. There are two poles included, and they stay in place because they are staked.

The best feature of the Aqua Quest is the extra-large netting and clear panel that allow visibility even when zipped inside. Although it takes a bit more effort to set up, this bivy does best at adding room above and is somewhat of a bivy/tent hybrid.

The Military Modular is different from the other brands because it includes customized bedding. This is a big plus in keeping warm and it makes the MM the best choice if you really need to rough it in cold weather.

All of the selections are highly rated for warmth in winter and for waterproofing. For warmer weather, the Snugpak and Military Module would be too hot and clingy. However, the Alpine and the Aqua Quest provide enough roominess and ventilation to be used with only a light covering inside in the summer.